Supposedly if you make a Mii named Nintendo he walks past the main menu screen occasionally, but I haven't seen any proof and have yet to test it out myself.
If you go to your mii plaza and don't move your cursor for like 10 seconds, the move it around it will draw all the Mii's attention.
On the last round of the Power Bowling training game, if you bowl your ball straight on top of either the left or right bumper wall, all the way to the back, you'll hear a tick and an explosion that gives you an automatic strike.
Hold a direction on the D-Pad when the screen goes black when loading Bowling to change the color of your ball between Red, Gold, Blue, and Green, I don't know which direction corresponds to what color though.
There's a couple other less interesting ones, like making the Tennis court blue by holding down 2 when the screen goes black when loading, or holding down 2 when its loading the Golf menu then when you play there's no HUD.
Linear Mode
